Plastic Grill Housing Repair

I will tell you what I did to my 69 Barracuda grill cracks. First, with a 1/16" drill bit, I drilled a hole at the end of the crack. This is called 'Stop Drilling'. It stops the crack from going further. Then I put a decent groove in the crack on the outside part that is visible from standing in front of the car. I folded a piece of 320 grit sandpaper and used the edge to cut the groove. Then I rounded out the edges of the groove for a smooth transition for the filler. You do not want a sharp corner; it will be harder to make the crack disappear when sanding filler. Make sure you groove and round out the 1/16" hole too. Then, on the back side of the grill, you need to reinforce the crack area. I do it with JB weld 5 minute epoxy and woven fiberglass cloth. I use the woven cloth because I like the strength, and I think it is a bit thinner and easier to work with. Scuff up the area on the back about 2" on either side of the crack with 320 grit sandpaper. Then cut a strip of the fiberglass cloth a little longer (maybe 1/4") than the crack and about 1" wide. Then cut a strip of the fiberglass cloth a little longer (maybe 1/2") than the 1" strip and about 3" wide. Then mix up enough epoxy to spread on the scuffed-up area (about 4" wide) and to work into the fiberglass cloth. Better to mix up a bit too much than having to stop and mix up a bit more. First, spread a film of epoxy on the scuffed-up area. Spread enough to soak into the fiberglass cloth. Then lay the 1" fiberglass strip over the crack making sure to try and center it over the crack and overlap the 1/16" hole. Make sure you have a glove on! with a fingertip, and a little more epoxy to the top of the 1" strip and work the strip into the epoxy below it. Smooth it out with your fingertip. You do not want any air in the patch. Then place the 3" wide strip on top of the 1" strip. Once again you will try to center the 3" patch over the 1" strip and overlap where the 1" strip covers the hole. with your gloved fingertip, place more epoxy on the patch and work it in and smooth it out. extend the epoxy a bit past the edge of the fiberglass cloth. Make sure the fiberglass cloth is not dry, but by the same token, don't smear on too much. After the epoxy cures, you can sand the epoxy patch area smooth. Then use some body filler to smooth out the fiberglass patch area on the back and to fill in the crack on the front. Sand it all smooth, apply primer, sand the primer smooth (probably ending up with 400 grit wet) and then paint it. I used Krylon Satin Black. The grills look pretty good and the repairs have held up very well.